The starting point for a successful marketing email is an enticing subject line.

After all, the subject line is often the only thing recipients see before deciding whether or not to open your email. If it doesn’t encourage recipients to open your email, nothing else you included in it matters.

And while we could give you a list of best practices to follow when crafting your email subject lines, we thought it might be more helpful to see some actual examples of subject lines that email marketers have used to drive above average open rates.

So we asked 42 marketers to dig through their email service providers’ metrics to find the subject line of the email they’ve sent that earned the highest open rate.

More than a third of our respondents shared subject lines that earned average open rates of 50% or more. The overall average open rate was 47%.

Below, we’ve listed each of our respondents’ best email subject lines, along with the actual results (when provided) and their notes on why they think the subject line performed so well.

Editor’s note: If you use Mailchimp and want a quick way to see how your marketing emails are performing, download this free Mailchimp dashboard to see metrics like list growth, audience activity, and campaign performance—all side-by-side in a central view.

The Best Email Subject Lines are Personalized

Many of our respondents’ highest-performing email subject lines were personalized—but not just in an “insert name here” kind of way. These subject lines work because they’re personalized based on what they know their recipients are interested in.

“You scratch my backlink, I scratch yours…”

“We sent this email in a campaign targeted at content marketers who we’ve exchanged backlinks with in the past,” Bibla says. “I think the high open rate was driven by the cheeky subject line and a compelling offer.”

“I wanted to make sure you received the invitation”

“For this email, we saw a drastic increase in open rate when we changed the subject line to be more personalized,” Smith says. “This email included a video invitation from a managing partner, so we took a more personalized approach since he was inviting the recipients of the email.”

“Historically, these types of emails see a 20-35% open rate when we send to this list, so this simple change had a huge impact on the open rate.”

“Did you still want [product]?”

“For our B2C client who sells physical products through an ecommerce store, we wanted to drive people back to their shopping carts if they failed to complete a purchase,” Hutchens says.

“To do this, we set up a simple workflow where if people add an item to their carts but don’t check out, we send a contextual email about the product to drive them back to their cart.”

“Instead of using a call-to-action like ‘come back to complete your purchase,’ we did a little wordsmithing with the email copy and created a sense of exclusivity, saying that their ‘shopping cart has been reserved.’ We also used a personalized subject line customized to what users last put in their carts.”

“[Report] 👏 Your copy of the Vendor Satisfaction report is inside 👏”

“This subject line performed so well because it was so targeted and relevant,” Pay says. “The recipients had all contributed to a survey that we based the report on, so they were invested in this report and had been primed about its release beforehand.”

“How you can get top 3 rankings with 70% less links”

“This is the first email I send out as part of a campaign when someone does a content upgrade on my blog,” White says.

“I think it does so well because our blog posts are all about doing better backlinking to get quicker rankings in Google, and this subject line speaks to that exact same problem.”

The Best Email Subject Lines are Timely

Another set of our respondents’ highest-performing subject lines achieved high open rates because they were timely—either in the sense that they refer to something that’s taking place right now, or because they refer to an action a visitor took recently.

Here are a few examples.

“📉 Correction: Corrections are normal…”

Results: Open rates were nearly 6% higher than their average and 8% higher than industry benchmarks

“This was a message to a list of subscribers who purchased and demonstrated an interest in the stock market and investing information products,” Donnachie says. “It was sent during the last month or so of 2018 at a time when the stock market was going through a severe correction.”

“The short subject line was accompanied by a pre-header that read: ‘Contrary to what you have heard, the sky isn’t falling.’”

“This subject line worked so well because this appeals to marketers on many different levels,” Lombardi says.

“The offer answered the question all marketers are curious about: ‘How do I stack up in the industry?’ The timing was especially important on this with beginning-of-the-year strategies being implemented and the excitement for what year will bring.”

“What happened? Your order didn’t come through…”

“This is one of the most important and popular email subject lines that we’ve used over the years—and still use today,” Agrawal says. “It gets sent out to anyone that starts to complete our form or order process but doesn’t complete it.”

“Not only is the open rate often above 20%, but it also has a high conversion rate to bring customers back to the site to complete their orders as well.”

“[First name]—if you’ve got it, haunt it.”

“I think this subject line worked very well for two reasons,” Schenker says. “First, the personalization of the recipients’ names right in the subject line is the very first element they see. Second, the use of unexpected humor tied into the season—it was a Halloween promo email.”

“We sent this email out on Amazon Prime Day while Amazon was experiencing technical difficulties,” Farahdel says. “The Amazon dogs would show up instead of what you searched for.”

“So we decided to include this in our subject line and have our own Prime Day sale. It worked very well. This shows how you can use certain events to your benefit.”

Editor’s note: Ecommerce marketers who use Mailchimp can see how their emails impact their entire funnel by downloading this Ecommerce Full Funnel dashboard that combines key metrics from Mailchimp, Google Analytics, Google Ads, and Facebook Ads.

The Best Email Subject Lines Pique Curiosity

Sometimes, the best email subject lines are very specific about the value a recipient will get by opening the email. Other times, it’s better to keep the value a secret and, instead, pique the recipient’s curiosity to inspire opens.

The results from these vague subject lines show how you can use curiosity to your advantage.

“It’s a very simple email subject—and of course is not always appropriate,” Morris says. “However, in certain circumstances, it can be a very powerful way of getting people to at least take an initial look at the content of your email body.”

“‘Quick question’ is my golden subject,” Szywalski says. “Some of our leads are hard to convert and classified as drop-outs, mainly due to lack of response. To these people, I send a manually written short message with a clear call to action using the ‘quick question’ subject line.”

“Broken Link”

“This subject line works well because it is short and to the point, while also having strong language,” Velez says. “I think having the term ‘broken’ in the subject line elicits a natural reaction of concern in recipients, causing them to open the message and check out what is wrong with their site.”

“Change Is Good Donkey”

“This subject line worked for several reasons,” Benson says. “First, it piqued recipients’ curiosity. Second, I hadn’t emailed the list in over a month, so it was new in their inboxes. Finally, I changed the ‘from’ email: previously it was info@ and now it’s members@.”

“👋”

“A lot of my emails are promotional,” Lane says. “Plain-text subject lines often let the recipient know it’s pretty promotional, and they’ll send it to the trash folder without much thought. But a waving-hand emoji is probably one of the vaguest subjects you’ll see.”

“It invokes a sense of curiosity (due to its vagueness), and since it’s a short, colored icon, it stands out among the other subject lines. It also comes off as more of a personal email—rather than a promotional one—which helps get the ball rolling in terms of success.”

“We have a special holiday surprise for you!”

“I think this subject line worked well for two reasons,” Hakopdjanian says. “First, by saying we have a special surprise, it makes the audience curious. Second, by saying that we have ‘a surprise for you,’ it makes the audience even more curious about what it is and how it can benefit them.”

“We’ve tested different email subject lines, and the ones that contain an element of mystery, surprise, suspense, or curiosity seem to work well for our open rates.”

“While ‘internship’ and ‘specialist’ are both eye-catching words, incorporating ‘opportunities’ in an email subject line is sure to successfully grab people’s attention,” Olmsted says. “No one wants an email selling them a product they’re not interested in.”

“But when words like ‘opportunity’ come up, this will grab someone’s attention enough for fear of missing out if they don’t open your email. Try adding positive words that entice people rather than turn them away in your email subject line to see if you can get a better open rate.”

“Congrats on saving so much money!”

“By making such a direct statement, we instilled a curiosity in the receiver which encouraged them to open the email, which I believe was the main driver behind the high open rate we achieved,” Smith says.

The Best Email Subject Lines are Simple

While highly specific and personalized emails sometimes inspire opens, other times it’s best to keep it simple and to the point. In fact, More than a third of our respondents said that their highest-performing subject lines contained fewer than 20 characters.

But simple doesn’t necessarily mean short. It may also mean the subject line is straightforward. Consider the examples below.

“Hi, [First name], Earn with Bernick’s!”

“The efficacy of this subject line surprised me at first,” Schroeder says. “Yet when I thought about it a little more, it didn’t. The simplicity and straightforwardness are what people are always going to trust and resonate with in marketing, and this email is proof of that.”

“Plus, it’s a great reminder that we don’t have to complicate efforts or always try to innovate and make things bigger, bolder, or more clickable. Be human. People like human.”

“New Product”

“I think this subject line worked for two reasons,” Stan says. “First, everyone likes to learn about a new product. Even though the subject line was short, it was enough to pique their curiosity to get them to click.”

“Second, over the years we’ve built our brand on being a trusted source in our industry. It is almost like when your boss sends you an email; you open it regardless of the subject line. Reputation plays an important role in our open rate.”

“5 Best Apps for 2019”

“This open rate came to me as a surprise because it was so simple and straight to the point,” Bentz says. “But I think that’s what made people want to open the email. They knew what they were getting right away.”

“[First name], Can I Help?”

“It’s a simple question, but it lets recipients know that we aren’t asking them to do anything,” Holloway says. “We just want to do something to help them, which in our case is to find them the right life insurance policy.”

“Coffee?”

“Interestingly enough, the simplest subject lines often have the highest open rates (similar to the fact that high-converting websites are often the most plain),” Askin says.

“I’ve used the subject line ‘Coffee?’ for job search efforts, product trials, and more, and invariably, it seems to elicit a similar response.”

The Best Email Subject Lines are Humanized

It helps to have your ‘from’ email set as a person rather than as your brand on your marketing emails. 70% of our respondents said their highest-performing emails were sent from a person:

But a simple ‘from’ email change may not be enough. It’s also important to have a subject line that sounds like it was written by one person for another. For example, Rob Powell Biz Blog’s Rob Powell says his highest-performing subject line is “The biggest mistake I ever made.”

Why does it work? It shows recipients that there’s a human behind the email.

Many of our respondents’ highest-performing subject lines work because they’re humanized. Here are several more examples.

“Where have you been all my life? 😎”

“I think too many companies take themselves too seriously and too many marketers fail to remember how much emotions and personal connections weigh into the decision to purchase a product or service,” Uhlir says.

“This subject line instantly lets the prospect know that they will be working with another person, not simply a helpdesk ticketing system or order-taker.”

“Do You Hate Me?”

“I think it works so well because it’s such a jarring question and it immediately arouses curiosity,” Pollard says. “I only use it to re-engage email subscribers who haven’t opened any of my last 20 emails. This is remarkable considering that these are people who didn’t open any other emails.”

“Something New, Just For You (You’re Really Going To Want To Read This One)”

“I believe this subject line worked so well because it gave my audience a firm directive,” Roberts says. “‘You’re going to want to read this one’ is basically a challenge, and it encourages my readers to say, ‘Oh you really think so?’ And then they open the email.”

“Email subject lines that foster engagement and reach out to the reader like this is a conversation tend to open best. Emails with conversational headlines have a more personalized flair and make it feel like I am emailing them as an individual—rather than a whole email list of subscribers.”

“Can you guide me?”

“I made some changes to my website and wanted to know the opinions of my readers,” Pande says. “I think the reason it worked is that people love giving suggestions, and if you ask them for their opinions, they feel honored.”

“You working this week?”

“I sent this email the week between Christmas and New Year’s,” Miller says. “The informal, friendly tone made it seem like a personal email.”

“The body of the email was about how I like to spend that week: thinking strategically about the year ahead and implying that we can provide strategy for our prospects.”

The Best Email Subject Lines Offer Value

Our final list of high-performing email subject lines focuses on telling recipients what value they’ll get by opening the email. Using these subject lines, our respondents have seen open rates as high as 85%.

“Looking for a good deal on SEO? How does 50% off sound?”

“In my professional opinion, the main reason why my subject line worked so well is because—let’s be honest—who wouldn’t be interested in getting anything at half of its original price?” Opulencia says.

“Another reason is that I made sure that the segment I sent it out to was scrubbed to remove any bad contacts and was only limited to small business owners who have healthy engagement scores, meaning they’ve downloaded a couple of our content offers.”

“That home equity you’ve earned—time to turn it into cash flow for your retirement!”

“People are naturally self-absorbed, and if they see the subject line as something that could potentially benefit them, chances are that their curiosity will be piqued enough to open the email for further details,” Freedman says.

“In this case, some may not know about the process behind reverse mortgages, so it piques their curiosity. And the idea that there is the potential of turning equity into cash flow for retirement naturally appeals to most seniors.”

“Before we go… Here are a few free resources.”

“We tested several variations of break-up emails for previously engaged leads, with this subject line being the clear winner,” Casey says.

“We used this as the last email on the unengaged side of a nurture workflow for inactive leads. Because the engagement levels were so low for this subsegment of leads, we afforded ourselves the opportunity to be bold with the concept of a break-up email.”

“In any exchange with a potential client, you need to constantly strive to add value. These free resources showed that our client wanted to continue adding value even if it didn’t benefit them directly.”

“Steal these hacks to stretch your marketing dollars💰”

“This subject line worked because it communicated the value of what was inside the email, used attention-grabbing words like ‘steal,’ addressed a very common pain point, and stood out in user’s inboxes by using an emoji,” Moxham says.

“How I used Facebook ads to get 2376 email subscribers in less than 3 days”

Best Practices for Writing Subject Lines that Generate Opens

But some are highly personalized while others are simple. Some are highly specific while others are vague to create intrigue. Some of these best practices seem to conflict with each other.

The best thing to do is to try each practice, test your results, and see which works best for specific campaigns and different segments.

Not every best practice will work for every list and campaign, but by testing and measuring results, you should be able to find the best approach for each audience’s specific needs.

About the author

Jessica Greene writes about marketing, business, and technology for B2B SaaS companies. A former writing instructor and corporate marketer, she uses her subject-matter expertise and desire to educate others as motivation for developing actionable, in-depth, user-focused content.